Electric Brakes Tested
Electrics Fare Well Against Pure Pneumatics
by Thomas Smith
May 10, 1887
Burlington, Iowa. Today is the second day of the Burlington Railway Brake Trials. During the past day, many inventions have been publicly tested for the first time. The trials are scheduled to continue through the rest of the spring, but the most interesting and important competitions are either over or scheduled for the next week.
The trials are happening because of the efforts of Iowa Railway Commissioner L. C. Coffin. He has been working for years to make safe brakes a standard for both passenger and freight trains. The most advanced brakes to date are those developed by the Westinghouse Brake Company. They use a purely pneumatic system to apply brakes all through the train. This arrangement is infinitely superior to the hand-operated brakes on top of the cars of old times. They work wonderfully for short passenger trains. Long freight trains, however, are beyond the scope of the current brake
technology. It takes the change in air pressure several seconds to travel through the whole train, causing the cars in the back to slam into the cars in the front, injuring the train personnel and shifting the freight. The brake trials are an effort to improve on this system, so that freight trains may have effective brakes.
Especially interesting were the systems put forth by the
Westinghouse Air Brake Comapany and by the Carpenter Company. Westinghouse's brakes are very similar to the common pure pneumatic brakes made by the same company. Rather than waiting for the air pressure to travel through the whole train, however, they electrically open a valve on a pressurized tube, at each car. This causes another valve to move so that a pressurized compartment in each car sends air into the brake chambers, pushing the brake pads against the wheels and therefore stopping the car. In the event of
a failure of the electricity, the resemblance to the old brakes pays off: they work in exactly the same way. A manual valve at the front of the train can also depressurize the same tube, although it does it more slowly.
The Carpenter Company's brakes are those invented by Mr. Herman Hollerith, with the funding of Mr. Carpenter. Also closely resembling the old Westinghouse brakes, and also using electricity, they are actually quite different from Westinghouse's entry in the trials. Rather than using electricity to aid the old depressurization mechanism, they use electricity to control the valves directly. This allows for a faster response time, by about 2 or 3 seconds. It also offers another important advantage: the force of the brakes can be finely controlled. The brakes do not need to
be full-on or full-off; they can go anywhere in between, rather like the brakes of an automobile. This is desirable, for instance, when going down a hill, where the speed of the train must be controlled. It is also desirable when the reserves of air must be preserved--it allows for more efficient usage of air. Like the new Westinghouse brakes, they retain the ability to use a manual pressure release mechanism in the event of an electrical failure.
The future of railway technology is an exciting one. Its
beginnings are becoming manifest here in Burlington, Iowa. Great inventions and ideas are taking shape. Updates on the trials will continue to come.
I wanted to touch on this aspect of Hollerith's career. The newspaper article is a good genre for this because I had the opportunity to explain the competing technologies.